Όσον αφορά την ηλεκτρονική θυρίδα, ο αριθμός πρωτοκόλλου εμφανίζεται τώρα.

Yes. Όσον αφορά is a very common fixed expression in formal Greek, especially in administrative, legal, and official writing.

It means something like:

• regarding
• as regards
• with regard to
• as far as ... is concerned

So here it introduces the topic: the sentence is saying something with respect to the electronic inbox/mailbox.

It is more formal than everyday alternatives such as σχετικά με.

Because αφορά takes a direct object, and direct objects in Greek normally go in the accusative.

So in Όσον αφορά την ηλεκτρονική θυρίδα:

• την = feminine singular accusative definite article
• ηλεκτρονική = feminine singular accusative adjective
• θυρίδα = feminine singular accusative noun

All three words agree with each other.

Literally, θυρίδα means something like small box, slot, compartment, or locker.

In digital or government-service contexts, ηλεκτρονική θυρίδα usually means a kind of:

• electronic inbox
• personal portal mailbox
• online message box/account area

So it usually does not mean ordinary email. It is more often a special inbox inside a website or official platform.

Because it is the thing that does the action of the verb εμφανίζεται.

Greek shows this through the nominative case:

• ο αριθμός = nominative singular masculine

Also, the verb is third person singular, which matches ο αριθμός.

So grammatically, the structure is:

• Όσον αφορά την ηλεκτρονική θυρίδα = topic frame
• ο αριθμός πρωτοκόλλου = subject
• εμφανίζεται τώρα = verb phrase

Greek uses the definite article more often than English does.

Here, ο αριθμός πρωτοκόλλου is a normal, natural way to say the protocol/reference number. Greek usually wants the article with a specific subject like this.

English can sometimes say things like reference number now appears in a very compressed, technical style, but Greek normally prefers ο αριθμός rather than leaving the noun bare in an ordinary sentence.

Πρωτοκόλλου is the genitive singular of πρωτόκολλο.

Greek often uses a noun + genitive structure where English might use either:

• of
• or a noun used like an adjective

So:

• αριθμός πρωτοκόλλου = literally number of protocol
• natural English: protocol number, registration number, or reference number

A similar example is:

• αριθμός τηλεφώνου = telephone number / phone number

In bureaucracy, πρωτόκολλο often refers to official registration in a filing or document-tracking system.

So αριθμός πρωτοκόλλου is the number assigned when a document, request, or submission is officially registered.

In practice, it often means:

• registration number
• filing number
• reference number

So this is an administrative term, not something about a scientific protocol or internet protocol.

Εμφανίζεται is:

• present tense
• third person singular
• morphologically a middle/passive form

But in meaning here, it works very naturally as:

• appears
• shows up
• is displayed

This is common in Greek. A passive-looking form can function in a way that English might translate either actively or passively depending on context.

For comparison:

• Το σύστημα εμφανίζει τον αριθμό πρωτοκόλλου = The system displays the reference number
• Ο αριθμός πρωτοκόλλου εμφανίζεται = The reference number appears / is displayed

Not necessarily.

Τώρα can mean:

• now, at this moment
• but also now, after a change
• or now, from this point onward

In software or platform messages, this often means something like:

• the number is now shown
• the number now appears
• the number is available/displayed now

So it may describe a new feature or updated behavior, not only something happening at this exact second.

The comma separates the introductory topic phrase from the main statement.

So the structure is similar to English:

• As for the electronic inbox, the reference number now appears.

This is a very normal use of a comma in Greek, especially in formal writing, when the sentence begins with a framing phrase like Όσον αφορά ...

Yes. Greek word order is fairly flexible.

The given order is natural and neutral for an official statement:

• Όσον αφορά την ηλεκτρονική θυρίδα, ο αριθμός πρωτοκόλλου εμφανίζεται τώρα.

But other orders are possible, with different emphasis. For example:

• Τώρα εμφανίζεται ο αριθμός πρωτοκόλλου.
  Emphasis on now

• Ο αριθμός πρωτοκόλλου εμφανίζεται τώρα.
  A simple neutral statement without the introductory topic phrase

• Στην ηλεκτρονική θυρίδα εμφανίζεται τώρα ο αριθμός πρωτοκόλλου.
  More direct focus on where it appears

So the original version is not the only possible one, but it sounds very natural in formal Greek.

It sounds fairly formal, administrative, and a bit bureaucratic/technical.

That comes mainly from:

• Όσον αφορά
• ηλεκτρονική θυρίδα
• αριθμός πρωτοκόλλου

A less formal or more everyday way to phrase something similar might be:

• Σχετικά με την ηλεκτρονική θυρίδα, ο αριθμός πρωτοκόλλου φαίνεται τώρα.
• Στην ηλεκτρονική θυρίδα φαίνεται τώρα ο αριθμός πρωτοκόλλου.

The original sentence is the kind of wording you might see in an official announcement, a government portal, or a system update notice.